Now that our own branches and tags are updated when git refs are
updated and the user can use them to specify revisions, we can start
displaying them instead of the git refs. This commit adds new
`branches` and `tags` template keywords and updates the default
templates to use them instead of `git_refs`.
I've often missed not having the timestamp there. It gets too long
with both email and timestamp for both author and committer, so I
removed the committer email to make room for the author timestamp.
I suspect that at least one reason that I didn't make
`MutableRepo::base_repo` by an `Arc<ReadonlyRepo>` before was that I
thought that that would mean that `start_transaction()` would need be
moved off of `ReadonlyRepo` so it can be given an
`&Arc<ReadonlyRepo>`, which would make it much less convenient to
use. It turns out that a `self` argument can actually be of type
`&Arc<ReadonlyRepo>`.
With lots of callbacks replaced by iterators, we are now ready to
propagate most cases of `BrokenPipe` errors to the top-level
`dispatch()` function where it gets ignored and we exit with an error
code.
I want to keep the index updated within the transaction. I tried doing
that by adding a `trait Index`, implemented by `ReadonlyIndex` and
`MutableIndex`. However, `ReadonlyRepo::index` is of type
`Mutex<Option<Arc<IndexFile>>>` (because it is lazily initialized),
and we cannot get a `&dyn Index` that lives long enough to be returned
from a `Repo::index()` from that. It seems the best solution is to
instead create an `Index` enum (instead of a trait), with one readonly
and one mutable variant. This commit starts the migration to that
design by replacing the `Repo` trait by an enum. I never intended for
there there to be more implementations of `Repo` than `ReadonlyRepo`
and `MutableRepo` anyway.
They're rendered as a single string created by joining the refs by
spaces because we don't have any support in the template language for
rendering a list.
I'm preparing to publish an early version before someone takes the
name(s) on crates.io. "jj" has been taken by a seemingly useless
project, but "jujube" and "jujube-lib" are still available, so let's
use those.
